Nintendo File Formats

NW > Sound > Sequence Sound (FSEQ)

This file contains a sequence sound. A sequence sound specifies which notes should be played at what time using instruments from a bank file.

Data Block

A sequence track consists of a stream of commands. These are stored in the data block. Every command starts with a single byte that specifies the type of the command, which is usually followed by one or more parameters (depending on the command).

Time is divided into beats, which are futher divided into ticks. The default number of beats per minute is 120, and the default number of ticks per beat is 48.

Some commands operate on variables. These are accessed by index, and can be divided into the following categories:

Command Table

Variable Length Int

Some commands take an integer of variable length. This integer is parsed as follows:

def read_varint():
    value = 0
    while True:
        byte = read_u8()
        value = (value << 7) | (byte & 0x7F)
        if not byte & 0x80:
            return value

Note Command

All commands between 0 and 127 play a note. The command number specifies the 'key'.

Sleep Command

Change Instrument Command

Start Track Command

Jump Command

This is a simple control flow command.

Set Ticks Per Beat Command

Set Beats Per Minute Command

Alloc Tracks Command

This command specifies the number of tracks that are allocated for this sequence sound. If present, this command must be the first command in the data block.

End Command

This command stops the current track.

Extended Command

This command starts with a single byte that indicates the type of its subcommand.

Variable Operation

Variable Comparison

This command compares a variable with a given value and writes the result (0 or 1) into the internal condition register of the command processor.

Label Block

Label

All labels are aligned to 4 bytes.